Britannica Educational Publishing 
Saudi Arabia and Yemen [PDF ebook] 

While they share a border and a rich heritage, Saudi Arabia and Yemen are also a study in contrasts. Where Saudi Arabia has a largely urban population that enjoys the benefits of its thriving economy, Yemen is home to predominantly rural citizens and is one of the poorest countries in the world. Within these pages, readers will encounter the long, intertwined histories of these two nations, as well as their individual struggles for prosperity and peace-with each other and the rest of the world.